[ltp] Patched x240 BIOS, Technoethical Wifi and blocked Trackpad

[Bjørn Mork]

Sébastien Lerique <sl at eauchat.org> writes:

> Dear list,
>
> First of all a great many thanks for thinkwiki.org, it has been of
> much support during many hours of missed sleep lately :-)
>
> I have an x240 for which I want to get wifi working with linux-libre,
> so I'm changing the wifi card.
>
> I bought a Technoethical N300DB
> <https://ryf.fsf.org/products/TET-N300DB>, which is an miniPCIe card,
> and a miniPCIe -> m2 adapter
> <https://www.aliexpress.com/i/33052961767.html>. I successfully
> patched my bios by using a raspberry pi and following the instructions
> at <https://www.thinkwiki.org/wiki/Custom_BIOS>, which links to
> <http://paranoid.anal-slavery.com/biosmods/xx40.html> for
> x240. (Successfully, at least in the sense that without the new wifi
> card everything works.)
>
> Now when I plug in the Technoethical Wifi card (with its miniPCIe ->
> m2 adapter), I have a curious problem: wifi works (mostly, I have a
> NetworkManager problem but that seems unrelated to my main question: I
> can see wifi networks but not yet connect to them), but my trackpad
> and trackpoint don't work any more (they normally do). If I power off,
> unplug the wifi card, and boot again, the trackpad and trackpoint
> work.
>
> It doesn't seem to be electromagnetic interference, as unplugging the
> antennas doesn't change anything. I also previously changed the x240
> clickpad with a normal x250 trackpad, but that also doesn't seem to
> have any role here as /both trackpad and trackpoint/ are not
> working. So I'm wondering, could this have something to do with the
> BIOS? I couldn't find any hints after searching online for quite some
> time. If you have any tips as to how I could troubleshoot this, it
> would be much appreciated!

Your m.2 slot might share some pins with the trackpad/trackpoint.  Pins
which are unconnected with the original WiFI module but not with the new
one.

This is a very common problem with USB ports being shared between an m.2
or mini-PCIe slot and some other connector.  But I guess the trackpad
and trackpoint aren't USB devices?

Still, it could be a similar problem with another bus.  Look at the
pinout of an m.2 or mini-PCIe WiFi slot, and try to cover any
optional/unused pins with e.g. a piece of tape.  This is probably
easiest to do on mini-PCIe with its larger and fewer pins.  Unless the
problem is related to the adapter.  But that should be pretty easy to
test by simply plugging it in without the WiFi module.

I assume the WiFi module only requires power and PCIe x1 signals.  But
it will use other optional pins for LEDs, wakeup, rf disable etc. Some
of these other signals might also be required, but probably not all of
them.  And there is a good chance that the collision is related to an
optional signal.


Bjørn